This is on the glass of a 10 gallon that I have set up for a white spotted hermit only thing in it is sand rock and some dragons breath. Seems to slowly be getting bigger.
It was some live rock from a tank I had about ten years ago. And stored in a container sense but I also started up a jbj 45 with the same rock and it is doing good corals fish and inverts. I scrubbed it real good and washed for about 10 minutes a rock